/*

 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.hotspot.amd64;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;

import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;

import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;

import org.graalvm.compiler.lir.LIRInstructionClass;

import org.graalvm.compiler.lir.Opcode;

import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import org.graalvm.compiler.lir.gen.DiagnosticLIRGeneratorTool.ZapStackArgumentSpaceBeforeInstruction;

import jdk.vm.ci.amd64.AMD64.CPUFeature;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.meta.Value;

/**

 * Returns from a function.

 */

@Opcode("RETURN")

final class AMD64HotSpotReturnOp extends AMD64HotSpotEpilogueBlockEndOp implements ZapStackArgumentSpaceBeforeInstruction {

    public static final LIRInstructionClass<AMD64HotSpotReturnOp> TYPE = LIRInstructionClass.create(AMD64HotSpotReturnOp.class);

    @Use({REG, ILLEGAL}) protected Value value;

    private final boolean isStub;

    private final Register scratchForSafepointOnReturn;

    private final GraalHotSpotVMConfig config;

    AMD64HotSpotReturnOp(Value value, boolean isStub, Register scratchForSafepointOnReturn, GraalHotSpotVMConfig config) {

        super(TYPE);

        this.value = value;

        this.isStub = isStub;

        this.scratchForSafepointOnReturn = scratchForSafepointOnReturn;

        this.config = config;

    }

    @Override

    public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {

        leaveFrameAndRestoreRbp(crb, masm);

        if (!isStub) {

            // Every non-stub compile method must have a poll before the return.

            AMD64HotSpotSafepointOp.emitCode(crb, masm, config, true, null, scratchForSafepointOnReturn);

            /*

             * We potentially return to the interpreter, and that's an AVX-SSE transition. The only

             * live value at this point should be the return value in either rax, or in xmm0 with

             * the upper half of the register unused, so we don't destroy any value here.

             */

            if (masm.supports(CPUFeature.AVX)) {

                masm.vzeroupper();

            }

        }

        masm.ret(0);

    }

}